[EVO 4G General] drmacinyasha:
Open ROM Manager.

Tap on "Flash ClockworkMod Recovery", then "HTC EVO (CDMA)". Give it root access when it asks. Give it a moment to download and flash the recovery. Press "OK" when it says that it's successfully flashed ClockworkMod recovery.

Scroll down to the bottom of ROM Manager's main menu, tap on "All ClockworkMod Recoveries", check "2.5.0.7", then "OK". Give it a moment to download and flash the recovery. Press "OK" when it says that it's successfully flashed ClockworkMod recovery.

Tap on "Download ROM", scroll down to the bottom, and tap on "EVO Stock and Radios". Once it loads, tap on "Combo Radio 2.15.00.05.02" (Make SURE to tap 05.02 and not 11.19!). Tap "Download" on the next screen. It'll take a few moments to download the ZIP.

Once the download is done, you'll get a pop-up saying there's an update for ClockworkMod recovery. Just hit OK to clear it. On the ROM Pre-Installation window, leave "Wipe Dalvik Cache" as checked. Tap OK. Tap OK on the next window.

The phone should then boot into ClockworkMod recovery and automatically flash the ZIP. After a few moments, you should see a black screen with a picture of a box opening, and pointing an arrow down into an Android. Then your phone will reboot again, show a similar screen with a little progress bar, reboot again, and you'll be back in your previous ROM, hopefully with updated radio, WiMAX, PRL, and NV!

Oh, open ROM Manager and tap on the Flash ClockworkMod Recovery button at the top again, so it will update ClockworkMod back to latest.

That will update your radios. To update to the latest stock ROM, make sure you've taken a backup using TitaniumBackup or something similar, then do the following:

If you can, connect to a stable WiFi network with a fast connection. You're going to be downloading about 200 MB for this.

Open ROM Manager.

Tap on "Flash ClockworkMod Recovery", then "HTC EVO (CDMA)". Give it root access when it asks. Give it a moment to download and flash the recovery. Press "OK" when it says that it's successfully flashed ClockworkMod recovery.

Tap on "Download ROM", scroll down to the bottom, and tap on "EVO Stock and Radios". Once it loads, tap on "4.24.651.1 Deodexed 6/21". Tap "Download" on the next screen. It'll take a few minutes to download the ZIP.

Once the download is done, in the ROM Pre-Installation window, leave "Wipe Dalvik Cache" as checked. Check "Backup Current ROM", and if you are not on a stock ROM (ie, if you're on CyanogenMod or anything else), check "Wipe Data and Cache". Tap OK. Tap OK on the next window.

The phone should then boot into ClockworkMod recovery and automatically take a Nandroid backup, then (if you were on a non-stock ROM and selected to wipe) wipe your data and cache. It will then flash the 4.24.651.1 ROM, and reboot back into Android once it's done.

If you have any issues (bootloops, etc.) first try manually re-flashing the file in ClockworkMod Recovery (the ZIP is located in /sdcard/clockworkmod/download/goo-inside.me/supersonic/stock). If you still have issues, try wiping dalvik and cache, and fixing permissions. If that doesn't solve it, wipe data and cache (again). If you still have issues after that, then restore your backup (ClockworkMod took one before flashing the ROM) and post back here, and we'll try to troubleshoot.